JP4254847B2 - Blow-by gas processing equipment - Google Patents

Description

  The present invention relates to a blow-by gas processing device provided in an internal combustion engine with a supercharger.

  As a device applied to internal combustion engines such as in-vehicle, ventilation of the combustion gas (blow-by gas) leaking into the crankcase from the gap between the cylinder and piston is performed, and the ventilated blow-by gas is recirculated into the intake air. Blow-by gas processing devices for processing are known. In the blow-by gas processing apparatus, the blow-by gas inside the engine is generally sucked into the intake passage by the intake negative pressure generated at the downstream side in the intake flow direction (hereinafter simply referred to as “downstream side”) from the throttle valve in the intake passage. Reflux during inspiration. In such an internal combustion engine with a blow-by gas processing device, the blow-by gas recirculated into the intake air is recombusted in the combustion chamber, so that the amount of hydrocarbon (HC) discharged into the atmosphere can be reduced. Further, the deterioration of oil due to blow-by gas can be suppressed by ventilation inside the engine.

  Here, in such a blow-by gas processing apparatus using intake negative pressure, the turbocharger is applied to an internal combustion engine provided with a supercharger (specifically, a compressor for pumping intake air) in the intake passage. When the intake negative pressure disappears with the operation of the engine, ventilation in the engine cannot be performed.

Conventionally, in a blow-by gas processing apparatus applied to an internal combustion engine not provided with a supercharger, a gas passing through the passage is pumped to a breather passage for discharging blow-by gas inside the engine to an intake passage. Providing a pump has been proposed (see, for example, Patent Document 1). By applying such a device to an internal combustion engine with a supercharger, it becomes possible to ventilate the engine even when the intake pressure is lost due to the operation of the supercharger (at the time of supercharging).
JP 2006-250080 A

  Certainly, as in the apparatus described in Patent Document 1, it is possible to ensure ventilation performance during supercharging by providing a pump for pumping gas in the breather passage. However, in such a device, it is necessary to drive the pump to ventilate the engine even when the supercharger is not operating and intake negative pressure is present (non-supercharging). Therefore, it cannot be said that efficient ventilation inside the engine is realized, and there is room for improvement in this respect.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a blow-by gas processing apparatus capable of efficiently ventilating blow-by gas inside an engine.

Hereinafter, means for achieving the above-described object and its operation and effects will be described.
The invention according to claim 1 is a supercharger that performs supercharging by pumping intake air flowing through an intake passage, and a throttle valve that variably sets a passage cross-sectional area of the intake passage downstream of the supercharger in the intake flow direction. Is applied to the internal combustion engine provided in the intake passage, communicates a portion of the intake passage downstream of the throttle valve in the intake flow direction and the inside of the engine, and allows only gas discharge from the inside of the engine to the intake passage. A first breather passage having a one-way discharge valve, and a second breather passage having a pump that communicates the intake passage and the inside of the engine and performs gas pumping from the inside of the engine to the intake passage. wherein the throttle valve to the intake flow direction upstream portion of the intake passage and with said engine internal and an introduction passage communicating, portion of the intake flow direction downstream side of the throttle valve in the intake passage As its gist to change the gas delivery amount of the pump on the basis of the section pressure.

  Since the intake negative pressure is generated during non-supercharging, the internal pressure (downstream pressure) at the downstream side in the intake flow direction (hereinafter simply referred to as “downstream side”) from the throttle valve in the intake passage is the throttle valve. It is lower than the internal pressure (upstream pressure) at the upstream side in the intake flow direction (hereinafter simply referred to as “upstream side”). Therefore, due to the difference between the downstream pressure and the upstream pressure, the intake air (outside air) flowing through the portion upstream of the throttle valve in the intake passage is introduced into the engine through the introduction passage, and the blow-by gas inside the engine is The air is sucked into the intake passage through one breather passage and recirculated into the intake air.

  On the other hand, at the time of supercharging, by driving the pump, the blow-by gas inside the engine is returned to the intake passage through the second breather passage and recirculated into the intake air, thereby reducing the blow-by gas inside the engine. Accordingly, intake air (outside air) flowing through the intake passage is introduced into the engine through the introduction passage.

  As described above, according to the above configuration, the inside of the engine can be ventilated using the intake negative pressure during non-supercharging and driving the pump during supercharging. Therefore, ventilation of the blow-by gas inside the engine can be performed efficiently.

The amount of blow-by gas that leaks from the combustion chamber into the engine varies depending on the downstream pressure. Further, the amount of gas discharged from the engine through the first breather passage due to the intake negative pressure also changes according to the downstream pressure. Therefore , according to the configuration in which the gas pumping amount of the pump is changed based on the internal pressure of the portion in the intake passage downstream of the throttle valve in the intake passage , the intake negative pressure is increased according to the amount of blow-by gas leaking into the engine. The gas pumping amount of the pump, in other words, the gas discharge amount from the inside of the engine through the second breather passage can be adjusted so as to compensate for the shortage of the gas discharge capability based on the above.

The gist of the invention described in claim 2 is that, in the blow-by gas processing apparatus according to claim 1, when the internal pressure is lower than a predetermined pressure, the driving of the pump is stopped.

  In the above configuration, when the downstream pressure is low, the driving of the pump is stopped, and the inside of the engine is ventilated through the first breather passage and the introduction passage. When the downstream pressure is high, the pump is driven to ventilate the engine through the second breather passage and the introduction passage. Thus, according to the above configuration, the pump can be driven efficiently by stopping the pump driving when the downstream pressure is low, instead of always driving the pump.

A third aspect of the present invention is the blowby gas processing apparatus according to the first or second aspect , wherein the pump has a lower temperature than the gas pumping amount when the temperature of the internal combustion engine is high. The gist is that the gas pumping amount is set to be large.

  The lower the temperature of the internal combustion engine, the lower the temperature of the lubricating oil and the temperature of the gas inside the engine, and contaminants such as unburned fuel in the blow-by gas are likely to enter the oil. In this regard, according to the above configuration, when the temperature of the internal combustion engine is low, the pumping capacity of the pump can be increased to increase the ventilation capacity, and contamination of oil can be suitably suppressed. it can. As the temperature of the internal combustion engine, in addition to directly detecting and using the same temperature, the temperature of the engine cooling water or the temperature of oil can be detected and used as the index value.

According to a fourth aspect of the present invention, in the blow-by gas processing apparatus according to any one of the first to third aspects, the second breather passage is an oil separator for separating oil from a gas passing through the passage. The processing apparatus further includes a return passage that communicates the inside of the oil separator and the inside of the engine.

  According to the above configuration, an oil separator having an oil separation capability commensurate with the gas flow rate in the second breather passage can be set, and the oil is appropriately separated from the gas passing through the second breather passage and separated. The discharged oil can be returned to the engine through the return passage.

The gist of a fifth aspect of the present invention is the blow-by gas processing apparatus according to the fourth aspect , wherein the oil separator is provided closer to the intake passage than the pump.

  In the above configuration, when the pump is driven, the pressure on the suction side (internal combustion engine side) is lower than the pressure on the discharge side (intake passage side), so the pressure inside the engine is lower than the internal pressure of the oil separator. Therefore, according to the above configuration, the oil separated by the oil separator can be efficiently returned to the inside of the engine by utilizing the pressure difference between the inside of the oil separator and the inside of the engine.

The invention according to claim 6 is the blow-by gas processing device according to any one of claims 1 to 5 , wherein the introduction passage is in a portion upstream of the supercharger in the intake passage in the intake air flow direction. The gist is to be connected.

  According to the above configuration, the pressure increased due to supercharging by the supercharger is not directly introduced into the engine, and it is possible to avoid an excessive increase in the pressure inside the engine during supercharging.

The invention according to claim 7 is the blow-by gas processing apparatus according to any one of claims 1 to 6 , wherein the second breather passage is upstream of the supercharger in the intake passage in the intake air flow direction. The gist is that it is connected to the part.

  According to the above configuration, compared with the configuration in which the gas is pumped by the pump to the portion of the intake passage that is downstream of the supercharger in the intake flow direction, that is, the portion where the internal pressure is extremely high during supercharging. The driving load of the pump during feeding can be reduced.

The invention according to claim 8 is the blow-by gas processing apparatus according to any one of claims 1 to 7 , wherein the first breather passage and the second breather passage are the same part inside the engine. The gist of the communication is

  Here, even if the blow-by gas is discharged and the outside air is introduced at the time of non-supercharging and at the time of supercharging, the blow-by gas is discharged from the engine or the outside air is introduced into the engine. In devices that differ between supercharging and non-supercharging, the flow of blow-by gas and the flow of outside air inside the engine are temporarily retained each time the operating state and non-operating state of the supercharger are switched. It will be greatly disturbed. Further, in a device in which the flow direction of blow-by gas and the flow direction of outside air in the communication passage communicating the intake passage and the inside of the engine are opposite in non-supercharging and supercharging, the blow-by gas in the communication passage The air is returned to the inside, or the outside air in the communication passage is returned to the intake passage. For this reason, none of these devices can efficiently replace the blow-by gas inside the engine with the outside air, that is, it cannot realize efficient ventilation of the blow-by gas inside the engine.

  According to the above configuration, the blow-by gas is discharged from the same portion (connecting portion of each breather passage inside the engine) into the intake passage regardless of whether the turbocharger is operated or not, and the same portion ( Since the outside air is introduced into the engine from the inside of the introduction passage), the flow direction of the blowby gas and the flow direction of the outside air in the engine can be made almost constant. Therefore, although the operation state of the turbocharger is switched between the operation state and the non-operation state, the flow of blow-by gas inside the engine and the flow of outside air are not greatly disturbed with this, and the ventilation of the blow-by gas inside the engine is efficiently performed. Can be done automatically.

(First embodiment)
Hereinafter, a first embodiment of a blow-by gas processing apparatus according to the present invention will be described.

FIG. 1 shows a specific configuration of the internal combustion engine according to the present embodiment.
As shown in FIG. 1, the internal combustion engine 10 includes a cylinder block 11. A cylinder head 12 is provided on the upper part of the cylinder block 11, and a head cover 13 is mounted on the upper part of the cylinder head 12. A crankcase 14 is formed at the lower part of the cylinder block 11, and an oil pan 15 is attached to the lower part of the crankcase 14. The oil pan 15 stores lubricating oil.

  A cylinder 16 is formed inside the cylinder block 11, and a piston 17 is disposed in the cylinder 16 so as to be capable of reciprocating. A combustion chamber 18 is defined in the internal combustion engine 10 by an inner peripheral wall of the cylinder 16, a top surface of the piston 17, and a lower surface of the cylinder head 12. An intake passage 20 is connected to the combustion chamber 18 via an intake valve 19, and an exhaust passage 22 is connected via an exhaust valve 21. A communication passage 23 is formed in the internal combustion engine 10 so as to communicate the inside of the head cover 13 with the crankcase 14.

  The internal combustion engine 10 is provided with an exhaust-driven supercharger 24. The supercharger 24 includes a turbine wheel 25 provided in the exhaust passage 22 of the internal combustion engine 10 and a compressor impeller 26 provided in the intake passage 20 of the internal combustion engine 10. The turbine wheel 25 and the compressor impeller 26 are connected via a shaft 27 so as to be integrally rotatable.

  When a large amount of exhaust gas is blown to the turbine wheel 25, the turbine wheel 25 also rotates together with the compressor impeller 26, whereby the intake air flowing through the intake passage 20 is pumped and the combustion chamber of the internal combustion engine 10 is compressed. 18 is forcibly sent. The supercharger 24 does not operate when the load on the internal combustion engine 10 is small and the exhaust amount is small (work amount≈ “0”), and operates when the load on the internal combustion engine 10 increases and the exhaust amount increases (work). Amount >> "0").

  In the intake passage 20 of the internal combustion engine 10, the temperature of the intake air is lowered through heat exchange with the air cleaner 28 that filters the intake air, the compressor impeller 26, and the atmosphere in order from the upstream side in the intake flow direction (hereinafter simply “upstream side”). An intercooler 29 and a throttle valve 30 as a throttle valve for variably setting the passage sectional area of the intake passage 20 are provided. The turbine wheel 25 is disposed in the exhaust passage 22 of the internal combustion engine 10. The internal combustion engine 10 is provided with a fuel injection valve (not shown). In the internal combustion engine 10, fuel is injected from the fuel injection valve and supplied into the combustion chamber 18.

  Further, in the internal combustion engine 10, the combustion gas leaked from the combustion chamber 18 into the crankcase 14 through the gap between the sliding surfaces of the cylinder 16 and the piston 17, that is, blow-by gas is returned to the intake air for processing. A blow-by gas processing device is provided.

  This blow-by gas processing apparatus has two passages (a first breather passage 41 and a second breather passage 42) for discharging blow-by gas from the inside of the engine (specifically, inside the crankcase 14) to the intake passage 20. And an introduction passage 43 for introducing intake air (outside air) from the intake passage 20 into the engine (specifically, inside the head cover 13).

  The first breather passage 41 is a passage that communicates a portion of the intake passage 20 that is downstream of the throttle valve 30 in the intake flow direction (hereinafter simply referred to as “downstream side”) and the inside of the crankcase 14. The end of the first breather passage 41 on the crankcase 14 side is connected to the crankcase 14 via a PCV valve 44.

  The PCV valve 44 is a differential pressure operating valve, and the opening degree of the PCV valve 44 is changed to a smaller opening degree as the pressure on the crankcase 14 side is higher than the pressure on the intake passage 20 side. The PCV valve 44 prohibits introduction of outside air from the intake passage 20 through the first breather passage 41 into the crankcase 14 and discharge of blow-by gas from the crankcase 14 to the intake passage 20 is allowed. . Further, the flow rate of blow-by gas discharged to the intake passage 20 through the first breather passage 41 by the PCV valve 44 depends on the difference between the pressure on the crankcase 14 side of the PCV valve 44 and the pressure on the intake passage 20 side. It is adjusted autonomously. In the present embodiment, the PCV valve 44 functions as a one-way discharge valve.

  The crankcase 14 is provided with an oil separator 45 for separating blowby gas and oil mist, and the end of the first breather passage 41 on the crankcase 14 side is connected to the oil separator 45. Has been. That is, the first breather passage 41 communicates with the crankcase 14 via the oil separator 45.

  The second breather passage 42 is a passage that communicates a portion of the intake passage 20 between the air cleaner 28 and the supercharger 24 and the inside of the crankcase 14. An electrically driven pump 46 is provided in the middle of the second breather passage 42. The pump 46 pumps the gas from the crankcase 14 side toward the intake passage 20 side. The blow-by gas inside the crankcase 14 is forcibly discharged into the intake passage 20 through the driving of the pump 46.

  The end of the second breather passage 42 on the crankcase 14 side is connected to the oil separator 45. That is, the first breather passage 41 and the second breather passage 42 are communicated with the same portion on the internal combustion engine 10 side.

  The introduction passage 43 is a passage that communicates a portion of the intake passage 20 between the air cleaner 28 and the supercharger 24 and the inside of the head cover 13. An end portion of the introduction passage 43 on the intake passage 20 side is connected to a portion upstream of the communication portion of the second breather passage 42.

  The apparatus according to the present embodiment is provided with various sensors for detecting the operating state of the internal combustion engine 10. As various sensors, for example, an accelerator sensor 51 for detecting an amount of depression of an accelerator pedal (not shown) (accelerator operation amount AC) and a rotation speed (engine rotation speed NE) of an engine output shaft (not shown) are detected. A speed sensor 52 is provided. In addition, a pressure sensor 53 for detecting an internal pressure (downstream pressure P1) in a portion downstream of the throttle valve 30 in the intake passage 20, and a temperature for engine cooling water (cooling water temperature THW) are detected. A temperature sensor 54 and the like are also provided.

  In addition, the apparatus according to the present embodiment includes an electronic control unit 50 configured by, for example, a microcomputer. The electronic control device 50 takes in the output signals of the various sensors, performs various calculations based on the signals, and controls the drive of the fuel injection valve (not shown) (fuel injection control) and pump based on the calculation results. Various controls relating to the operation of the internal combustion engine 10, such as drive control (pump control) 46, are executed.

  In the fuel injection control, a control target value (target fuel injection amount Qm) for the fuel injection amount from the fuel injection valve is calculated based on the operating state of the internal combustion engine 10 such as the accelerator operation amount AC and the engine speed NE. At the same time, the fuel injection valve is driven to open and close according to the target fuel injection amount Qm. Thereby, an amount of fuel commensurate with the operating state of the internal combustion engine 10 is injected from the fuel injection valve.

  Further, in the fuel injection control, when the coolant temperature THW is low, processing for increasing the fuel injection amount from the fuel injection valve (specifically, the target fuel injection amount Qm) (increase correction processing) is executed.

  When the temperature of the internal combustion engine 10 is low, a part of the injected fuel does not burn in the combustion chamber 18 because it adheres to the wall surface of the combustion chamber 18. Such a phenomenon is not preferable because the operation state of the internal combustion engine 10 becomes unstable due to insufficient torque of the internal combustion engine 10. The increase correction process is executed to avoid such inconvenience. The amount of fuel that does not burn in the combustion chamber 18 described above increases as the temperature of the internal combustion engine 10 decreases. In view of this point, in the increase correction process, the fuel injection amount is increased more as the temperature of the internal combustion engine 10 (specifically, the coolant temperature THW as the index value) is lower.

  On the other hand, the pump control is executed based on the downstream pressure P1. Specifically, when the supercharger 24 is not operating and the downstream pressure P1 is low (there is a so-called intake negative pressure), the drive of the pump 46 is stopped. Further, when the downstream pressure P1 is high due to the operation of the supercharger 24 (when there is no intake negative pressure), the pump 46 is driven.

Hereinafter, the operation of the blow-by gas processing apparatus according to the present embodiment will be described.
First, since the intake negative pressure is generated when the supercharger 24 is not operating (non-supercharge), the internal pressure (upstream pressure P2) of the portion of the intake passage 20 upstream of the supercharger 24 is increased. ), The downstream pressure P1 becomes lower. Therefore, due to the difference between the downstream pressure P1 and the upstream pressure P2, the intake air (outside air) flowing through the portion upstream of the supercharger 24 in the intake passage 20 as shown by the black arrow in FIG. While being introduced into the engine through the introduction passage 43, blow-by gas inside the engine is sucked into the intake passage 20 through the first breather passage 41 and recirculated into the intake air.

FIG. 2 shows the relationship between the gas flow rate in the first breather passage 41 and the downstream pressure P1.
As shown in FIG. 2, at the time of non-supercharging when the downstream pressure P1 is low, only the gas discharge from the engine through the first breather passage 41, that is, the gas discharge using the downstream pressure P1 (intake negative pressure). Thus, an amount of gas exceeding the amount of blow-by gas that leaks into the crankcase 14 per unit time (the amount indicated by the one-dot chain line in the figure) is discharged from the engine to the intake passage 20.

FIG. 3 shows the relationship between the gas flow rate in the second breather passage 42 and the downstream pressure P1.
As shown in FIG. 3, when the downstream pressure P1 is lower than the predetermined pressure α, the driving of the pump 46 is stopped, and only ventilation inside the engine using the intake negative pressure is executed. Thereby, the blow-by gas inside the engine is sufficiently ventilated during non-supercharging when the downstream pressure P1 is low.

  As described above, in the apparatus according to the present embodiment, the ventilation function of the blow-by gas is ensured by ventilating the inside of the engine using the intake negative pressure during non-supercharging. The pump 46 is not always driven, but when the downstream pressure P1 is low, that is, when the inside of the engine can be ventilated by the negative intake pressure, the pump 46 is stopped and the pump 46 is driven efficiently. Is done.

  On the other hand, when the downstream pressure P1 increases due to the operation of the supercharger 24, the intake negative pressure disappears and the discharge of blow-by gas through the first breather passage 41 is stopped (see FIG. 2). However, in the apparatus according to the present embodiment, as shown in FIG. 3, when the downstream pressure P <b> 1 is equal to or higher than the predetermined pressure α, the pump 46 is driven and the gas inside the engine is sucked through the second breather passage 42. It is forcibly fed into the passage 20. As a result, as shown by the white arrow in FIG. 1, the blow-by gas inside the engine is returned to the intake passage 20 through the second breather passage 42 and recirculated into the intake air, and the gas inside the engine is reduced. Accordingly, intake air (outside air) flowing through the intake passage 20 is sucked and introduced into the engine through the introduction passage 43. 3 indicates the amount of blow-by gas that leaks into the crankcase 14 per unit time.

  Here, in the internal combustion engine 10, the amount of blow-by gas that leaks from the combustion chamber 18 into the crankcase 14 changes in accordance with the downstream pressure P1. Specifically, the amount of blow-by gas that leaks into the crankcase 14 increases as the downstream pressure P1 increases. Further, the amount of gas discharged from the engine through the first breather passage 41 due to the intake negative pressure also changes according to the downstream pressure P1 (see FIG. 2). Based on this point, in the pump control of the present embodiment, the gas pumping amount of the pump 46 is changed based on the downstream pressure P1.

  FIG. 4 shows the amount of gas discharged from the engine into the intake passage 20 (specifically, the sum of the gas flow rate in the first breather passage 41 and the gas flow rate in the second breather passage 42) and the downstream pressure P1. Show the relationship.

  As shown in FIG. 4, in detail, in the pump control, the gas discharge amount exceeds the amount of blow-by gas that leaks into the crankcase 14 per unit time (the amount indicated by the one-dot chain line in FIG. 4). In addition, the pump 46 is driven in a manner corresponding to the downstream pressure P1. By driving the pump 46 in this way, the shortage of the gas discharge capacity based on the intake negative pressure is compensated according to the amount of blow-by gas leaking into the crankcase 14 that changes with the downstream pressure P1. In addition, the gas pumping amount of the pump 46, in other words, the gas discharge amount from the engine through the second breather passage 42 is adjusted. Thereby, the blow-by gas inside the engine is sufficiently ventilated. As described above, in the present embodiment, the blow-by gas ventilation function is ensured through the driving of the pump 46 even at the time of supercharging when the intake negative pressure decreases or disappears because the downstream pressure P1 is high.

  In the present embodiment, since the introduction passage 43 is connected to a portion of the intake passage 20 upstream of the supercharger 24, the pressure increased by supercharging by the supercharger 24 is directly applied to the inside of the engine. Without being introduced, it is possible to avoid an excessive increase in the pressure inside the engine during supercharging.

  Further, in the present embodiment, since the second breather passage 42 is connected to a portion of the intake passage 20 upstream of the supercharger 24, a portion downstream of the supercharger 24, that is, an excess portion. Compared with the configuration in which the gas is pumped by the pump 46 to the portion where the internal pressure becomes extremely high at the time of supply, the driving load of the pump 46 at the time of supercharging can be kept low.

  Incidentally, in the apparatus according to the present embodiment, when some trouble occurs in the internal combustion engine 10 and a large amount of blow-by gas leaks from the combustion chamber 18 into the crankcase 14, the engine is introduced through the introduction passage 43. It is possible to suppress the internal gas from being discharged into the intake passage 20 and the pressure inside the engine from becoming excessively high. Therefore, for example, it is possible to suppress a decrease in the reliability of the seal member for preventing gas outflow from the inside of the engine to the outside and gas intrusion into the engine, and the reliability of the internal combustion engine 10 is suppressed from decreasing. .

  Here, even if the blow-by gas is discharged and the outside air is introduced at the time of non-supercharging and at the time of supercharging, the blow-by gas is discharged from the engine or the outside air is introduced into the engine. In different configurations between supercharged and non-supercharged, the flow of blow-by gas and the flow of outside air inside the engine are temporarily retained each time the operating state and non-operating state of the turbocharger are switched. It will be greatly disturbed. In the configuration in which the flow direction of the blow-by gas and the flow direction of the outside air in the communication passage connecting the intake passage and the inside of the engine are opposite in non-supercharging and supercharging, the blow-by gas in the communication passage The air is returned to the inside, or the outside air in the communication passage is returned to the intake passage. Therefore, none of these configurations can efficiently replace the blow-by gas inside the engine with the outside air, that is, it is impossible to realize efficient ventilation of the blow-by gas inside the engine.

  In this regard, in the present embodiment, the direction in which the blow-by gas flows in the first breather passage 41 and the second breather passage 42 is always constant, and the direction in which the outside air flows in the introduction passage 43 is always constant. It is. Therefore, when the operating state and the non-operating state of the supercharger 24 are switched, the blow-by gas in the first breather passage 41 or the blow-by gas in the second breather passage 42 flows backward, or in the introduction passage 43. There is no backflow of outside air.

  Further, regardless of whether the supercharger 24 is activated or not, blow-by gas is discharged from the same part inside the engine (specifically, the part where the oil separator 45 is attached to the crankcase 14), and the same part inside the engine. Specifically, outside air is introduced into the head cover 13 where the oil separator 47 is attached. Therefore, the flow direction of blow-by gas and the flow direction of outside air inside the engine can be made almost constant. Therefore, although the operation state and the non-operation state of the supercharger 24 are switched, the flow of blow-by gas inside the engine and the flow of outside air are not greatly disturbed, and ventilation of the blow-by gas inside the engine is not affected. Can be done efficiently.

As described above, according to the present embodiment, the effects described below can be obtained.
(1) The inside of the engine can be ventilated by using the intake negative pressure at the time of non-supercharging and by driving the pump 46 at the time of supercharging, and the blow-by gas inside the engine can be efficiently ventilated.

  (2) The gas pumping amount of the pump 46 is changed based on the downstream pressure P1. For this reason, the gas pressure feed of the pump 46 is made up to compensate for the shortage of gas discharge capacity due to the intake negative pressure according to the amount of blow-by gas leaking into the crankcase 14 from the combustion chamber 18 that changes with the downstream pressure P1. The amount, in other words, the amount of gas discharged from the engine through the second breather passage 42 can be adjusted.

  (3) The pump 46 is not driven at all times, but when the downstream pressure P1 is low, that is, when the inside of the engine can be ventilated by the negative intake pressure, the pump 46 is stopped so that the efficiency of the pump 46 is improved. It can drive well.

  (4) Since the introduction passage 43 is connected to the upstream side of the supercharger 24 in the intake passage 20, it is possible to avoid excessively high internal pressure during supercharging.

  (5) Since the second breather passage 42 is connected to the upstream side of the supercharger 24 in the intake passage 20, the gas pressure is sent by the pump 46 to the downstream side of the supercharger 24. Compared with the structure which performs, the drive load of the pump 46 at the time of supercharging can be restrained low.

  (6) Since the first breather passage 41 and the second breather passage 42 communicate with the same part in the engine, the operating state and the non-operating state of the supercharger 24 are switched. Along with this, the flow of blow-by gas inside the engine and the flow of outside air are not greatly disturbed, and the blow-by gas inside the engine can be ventilated efficiently.

(Second Embodiment)
Hereinafter, a second embodiment in which the blow-by gas processing apparatus according to the present invention is embodied will be described focusing on differences from the first embodiment.

  In the first embodiment, only the downstream pressure P1 is used as a setting parameter for setting the gas pumping amount of the pump 46. On the other hand, in the present embodiment, the cooling water temperature THW is used as such a setting parameter in addition to the downstream pressure P1. Only in this respect, the apparatus according to the present embodiment is different from the apparatus according to the first embodiment.

  Here, when the temperature of the internal combustion engine 10 is low, the fuel injection amount is increased by the increase correction process described above. The degree of increase in the fuel injection amount in the increase correction process is larger as the temperature of the internal combustion engine 10 (specifically, the coolant temperature THW) is lower. Therefore, it can be said that the lower the temperature of the internal combustion engine 10, the greater the amount of contaminants such as unburned fuel contained in the blow-by gas that leaks from the combustion chamber 18 into the crankcase 14. Further, the lower the temperature of the internal combustion engine 10, the lower the gas temperature and the oil temperature inside the engine, so that contaminants in the blow-by gas are likely to be mixed into the oil.

  Therefore, in order to suppress the deterioration of oil due to blow-by gas, the lower the temperature of the internal combustion engine 10, the larger the amount of gas discharged from the engine and the amount of outside air introduced into the engine. It is desirable to increase the value.

Based on this point, in the present embodiment, pump control is executed so that the gas pumping amount of the pump 46 increases as the temperature of the internal combustion engine 10 decreases.
Hereinafter, the pump control will be specifically described.

FIG. 5 shows the relationship between the amount of gas discharged from the engine and the downstream pressure P1 when the coolant temperature THW is a predetermined temperature.
As shown in FIG. 5, in the pump control of the present embodiment, the temperature of the internal combustion engine 10 (specifically, when the warm-up of the internal combustion engine 10 is completed (for example, the coolant temperature THW ≧ 80 degrees) When the coolant temperature THW as the index value is high, the gas pumping amount of the pump 46 is set so that the gas pumping amount (the amount indicated by the line L1 in the figure) corresponds to the downstream pressure P1. . That is, at this time, the pump control of the present embodiment is executed in the same manner as the pump control of the first embodiment.

  On the other hand, when the cooling water temperature THW is low, the gas pumping amount (L1) corresponding to the downstream pressure P1 is increased by the amount corresponding to the cooling water temperature THW (the amount indicated by the line L2 in the figure). Thus, pump control is executed. As the increase correction amount (the amount corresponding to the hatched portion in the figure) for the gas pumping amount, a larger amount is set as the cooling water temperature THW is lower.

  According to the apparatus according to the present embodiment, when the temperature of the internal combustion engine 10 is low and oil deterioration due to blow-by gas is likely to occur, the gas pumping amount of the pump 46 is increased in accordance with the temperature to ventilate the engine. The performance can be increased. Accordingly, it is possible to suitably suppress contamination of the oil into the oil, and hence oil deterioration due to blow-by gas.

As described above, according to the present embodiment, in addition to the effects described in (1) to (6), the effect described in (7) below can be obtained.
(7) Oil deterioration due to blow-by gas can be suitably suppressed.

(Other embodiments)
Each of the above embodiments may be modified as follows.
In the first embodiment, the pump 46 may be driven even when the downstream pressure P1 is lower than the predetermined pressure α. According to this configuration, when only the gas discharge from the inside of the engine by the negative intake pressure is executed, there is a device that causes a shortage of the gas discharge amount even when the downstream pressure P1 is lower than the predetermined pressure α. Can be supplemented through gas pumping by the pump 46.

  In the second embodiment, when the cooling water temperature THW is lower than the predetermined temperature, the gas pumping amount of the pump 46 is increased by a predetermined amount, while when the cooling water temperature THW is equal to or higher than the predetermined temperature, the pump 46 is increased. The pump control may be executed so that the gas pumping amount is not increased.

  In the second embodiment, instead of the cooling water temperature THW among the setting parameters, other index values for the temperature of the internal combustion engine 10 such as oil temperature, for example, may be detected and used. Good. It is also possible to directly detect the temperature of the internal combustion engine 10 and use it as a setting parameter.

  In each embodiment, the drive system of the pump 46 is a system other than the electric drive system, for example, an engine drive system driven using the rotation of the engine output shaft, or an oil drive system operated using oil pressure. It may be changed to.

  In each embodiment, as shown in FIG. 6, an oil separator 60 for separating oil is newly provided in a portion of the second breather passage 42 closer to the intake passage 20 than the pump 46. You may make it provide the return channel | path 61 which connects 60 inside and crankcase 14 inside.

  According to such a configuration, it is possible to set the oil separator 60 having an oil separation capability corresponding to the gas flow rate in the second breather passage 42, and to appropriately separate the oil from the gas passing through the second breather passage 42. At the same time, the separated oil can be returned to the engine through the return passage 61.

  In the above configuration, when the pump 46 is driven, the pressure on the suction side (internal combustion engine 10 side) is lower than the pressure on the discharge side (intake passage 20 side). Pressure is lowered. According to the above configuration, the oil separated by the oil separator 60 can be efficiently returned to the inside of the engine using the pressure difference between the inside of the oil separator 60 and the inside of the engine.

In the apparatus shown in FIG. 6, the position of the oil separator 60 may be changed to a portion of the second breather passage 42 closer to the internal combustion engine 10 than the pump 46.
-The blow-by gas processing apparatus concerning each embodiment is applicable also to the apparatus in which the increase correction process is not performed.

In each embodiment, the end portion of the second breather passage 42 on the intake passage 20 side may be connected to a portion of the intake passage 20 on the downstream side of the supercharger 24.
In each embodiment, if it is possible to avoid an excessive increase in pressure inside the engine during supercharging, the introduction passage 43 is provided between the supercharger 24 and the throttle valve 30 in the intake passage 20. You may make it connect to this part.

  The first breather passage 41 and the second breather passage 42 are connected to the oil separator 47 provided in the head cover 13, and the introduction passage 43 is connected to the oil separator 45 provided in the crankcase 14. Good.

  In addition, two oil separators are provided at different positions of the head cover 13, and the introduction passage 43 is connected to one oil separator, and the first breather passage 41 and the second breather passage 42 are connected to the other oil separator. It may be. In this configuration, the internal structure of the internal combustion engine 10 is blown from the crankcase 14 to the head cover 13 by, for example, devising the shape of the communication passage 23 that connects the inside of the head cover 13 and the inside of the crankcase 14. It is desirable to adopt a structure in which gas introduction and outside air introduction from the head cover 13 to the crankcase 14 are appropriately performed.

  Further, two oil separators are provided at different positions inside the crankcase 14, and the introduction passage 43 is connected to one of the oil separators, and the first breather passage 41 and the second breather passage 42 are connected to the other oil separator. It is also possible to do.

  It is widely known that oil sludge generated due to oil deterioration is mainly generated in the cylinder head 12 or the head cover 13 based on blow-by gas. Therefore, in order to suppress the generation of oil sludge, it is desirable to adopt a structure in which the introduction passage 43 is connected to the head cover 13 and the outside air is directly fed into the head cover 13.

  When such a structure is employed, it is desirable to connect the first breather passage 41 and the second breather passage 42 to the crankcase 14. As a result, it becomes possible to push out the gas including the blow-by gas inside the engine by the outside air in the order of “inside the head cover 13 → the crankcase 14 → the intake passage 20”, and the entire inside of the engine can be efficiently ventilated.

  In each embodiment, the oil separator 45 can be omitted if oil intrusion into the first breather passage 41 and the second breather passage 42 from the inside of the engine is avoided. Further, the oil separator 47 can be omitted if oil intrusion into the introduction passage 43 from the inside of the engine is avoided.

  In the internal combustion engine of the V-type cylinder arrangement, a configuration is adopted in which the introduction passage is connected to the head cover of each bank and the first breather passage and the second breather passage are connected to the crankcase. be able to. Further, in the internal combustion engine of the V-type cylinder arrangement, the introduction passage is connected to the head cover of one bank, and the first breather passage and the second breather passage are connected to the head cover of the other bank. It can also be adopted. Further, in the internal combustion engine of the V-type cylinder arrangement, the introduction passage is connected to the crankcase, and the first breather passage and the second breather passage are respectively connected to the head cover of each bank. It is also possible to do.

-In each embodiment, you may make it connect the edge part by the side of the internal combustion engine of a 1st breather channel | path and a 2nd breather channel | path to a different part.
The present invention is not limited to an internal combustion engine equipped with an exhaust-driven supercharger, but can also be applied to an internal combustion engine equipped with an engine-driven supercharger, a so-called supercharger. The present invention can also be applied to an internal combustion engine that is not provided with an intercooler.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows schematic structure of the blowby gas processing apparatus concerning 1st Embodiment which actualized this invention. The schematic diagram which shows the relationship between the gas flow rate of a 1st breather channel | path, and downstream pressure. The schematic diagram which shows the relationship between the gas flow rate of a 2nd breather channel | path, and downstream pressure. 6 is a schematic diagram showing the relationship between the amount of gas discharged from the inside of the engine to the intake passage and the downstream pressure. 6 is a schematic diagram showing the relationship between the amount of gas discharged from the inside of the engine and the downstream pressure when the coolant temperature is a predetermined temperature. Schematic which shows schematic structure of the blowby gas processing apparatus concerning other embodiment which actualized this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Cylinder block, 12 ... Cylinder head, 13 ... Head cover, 14 ... Crankcase, 15 ... Oil pan, 16 ... Cylinder, 17 ... Piston, 18 ... Combustion chamber, 19 ... Intake valve, 20 ... Intake Passage, 21 ... exhaust valve, 22 ... exhaust passage, 23 ... communication passage, 24 ... supercharger, 25 ... turbine wheel, 26 ... compressor impeller, 27 ... shaft, 28 ... air cleaner, 29 ... intercooler, 30 ... throttle valve , 41 ... first breather passage, 42 ... second breather passage, 43 ... introduction passage, 44 ... PCV valve, 45, 47,60 ... oil separator, 46 ... pump, 50 ... electronic control device, 51 ... accelerator sensor 52 ... Speed sensor, 53 ... Pressure sensor, 54 ... Temperature sensor, 61 ... Return path.

Claims (8)

An internal combustion engine in which a supercharger that performs supercharging through pumping of intake air flowing through the intake passage and a throttle valve that variably sets the cross-sectional area of the intake passage downstream of the supercharger in the intake flow direction are provided in the intake passage Applies to institutions,
A first breather passage having a one-way discharge valve that communicates a portion of the intake passage downstream of the throttle valve in the intake flow direction and the inside of the engine and allows only gas discharge from the inside of the engine to the intake passage;
A second breather passage having a pump that communicates the intake passage and the inside of the engine and performs gas pressure feeding from the inside of the engine to the intake passage;
An introduction passage that communicates a portion of the intake passage upstream of the throttle valve with respect to the intake flow direction and the engine interior ;
The gas pumping amount of the pump is changed based on the internal pressure of the portion in the intake passage downstream of the throttle valve in the intake flow direction.
The blow-by gas processing apparatus characterized by the above-mentioned. The blow-by gas processing apparatus according to claim 1,
The blow-by gas processing apparatus , wherein the pump is stopped when the internal pressure is lower than a predetermined pressure . In the blowby gas processing apparatus according to claim 1 or 2,
The blow-by gas processing apparatus according to claim 1, wherein the pump is configured such that a gas pumping amount when the temperature is low is set larger than a gas pumping amount when the temperature of the internal combustion engine is high . In the blowby gas processing apparatus according to any one of claims 1 to 3,
The second breather passage is provided with an oil separator for separating oil from the gas passing through the passage.
The blow-by gas processing device, wherein the processing device further includes a return passage communicating the oil separator and the engine . In the blowby gas processing apparatus according to claim 4 ,
The blow-by gas processing apparatus, wherein the oil separator is provided closer to the intake passage than the pump . In the blowby gas processing apparatus according to any one of claims 1 to 5 ,
The blow-by gas processing apparatus , wherein the introduction passage is connected to a portion of the intake passage upstream of the supercharger in the intake flow direction . In the blowby gas processing device according to any one of claims 1 to 6,
The blow-by gas processing apparatus, wherein the second breather passage is connected to a portion of the intake passage upstream of the supercharger in the intake flow direction . In the blowby gas processing apparatus according to any one of claims 1 to 7,
The blow-by gas processing apparatus, wherein the first breather passage and the second breather passage are communicated with the same part in the engine .

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